This invention relates generally to continuous towel dispensers and is particularly directed to a continuous towel dispenser which employs solid state sensing and control circuitry as well as a novel towel withdrawing sensor arrangement.
Continuous towel dispensers typically include a cabinet containing a supply roll of clean toweling. The roll of clean toweling is generally supported in the cabinet in a manner to allow its rotation to permit the clean toweling to be dispensed from the cabinet. The clean toweling is commonly fed out of a front or lower portion of the cabinet via a slot therein so as to form a towel loop which hangs beneath the cabinet. The front or forward leg of the loop is in the use position and is grasped and pulled down during a use cycle. The towel loop also includes a rear leg which extends upward into the dispenser cabinet through a suitable intake slot therein. The thus retracted soiled toweling is then wound onto an uptake roller for storage in the cabinet at the start of each use cycle. Examples of continuous towel dispensers of this type can be found in U.S. Pat. Nos. 3,858,953 and 3,893,738, both assigned to the assignee of the present application.
The soiled towel loop is automatically withdrawn from its use position into the cabinet when a user has completed the drying operation. Automatic roll-up of the soiled towel avoids the unpleasant appearance of the exposed soiled toweling as well as the possibility of the next user contacting the previously soiled toweling.
In some dispensers, discharge of the clean toweling as well as release of a predetermined section of used toweling is initiated by user responsive actuating means. In this type of dispenser it is not necessary for the user to first grasp and then pull out the clean toweling as this is accomplished automatically by user actuation. The actuation means may be in the form of a mechanical or electromechanical switch typically on the dispenser cabinet which is engaged by the user for clean toweling release. Another well known arrangement makes use of a light beam which is interrupted when the user's hands are positioned in contact with or in the vicinity of the toweling. The latter arrangement, which typically makes use of an infrared (IR) beam, employs a photocell. U.S. Pat. No. 4,676,131, also assigned to the assignee of the present application, discloses a paper towel dispenser employing the combination of a phototransistor and a light emitting diode (LED) responsive to the presence of a user's finger or hand in a recess in the dispenser cabinet for initiating automatic dispensing of a selected length of paper towel. The use of mechanical switches limits the reliability of the towel dispenser, while the opto coupler arrangement increases dispenser complexity and renders it more susceptible to extraneous inputs causing unwanted towel release.
In addition, prior art towel discharge and takeup sensors and controllers have been somewhat imprecise in the length of toweling released and rolled up during each use cycle. The payout of precisely measured clean towel lengths each cycle is highly desirable from a user's standpoint, while imprecise roll-up of the used toweling will result in towel storage problems. More specifically, the used, soiled toweling requires more space to store than the clean toweling. It is therefore essential that the used toweling be tightly wound around the takeup roll to permit all of the toweling, after use, to be stored within the dispenser cabinet.
The present invention provides all of the aforementioned desirable operating features in a continuous towel dispenser and thus overcomes the limitations of the prior art by affording an electronic controller for a continuous towel dispenser which makes use of a novel sensor arrangement, employs solid state electronics, and permits various operating parameters of the dispenser to be established as desired. The novel sensor arrangement makes the present invention highly insensitive to extraneous inputs from the environment, while the unique control arrangement of the present invention permits the towel to remain in the extended, use configuration as long as it is engaged by a user and to be automatically retracted after it is used.